Loop-taker for sewing machines



Marchvlll, 1944. s, zoNls 2,343,877

Loop TAKER FOR SEWING MACHINES Filed Jan. 8, 1942 Patented Mar. 14, 1944 2,343,877 Looe-Tanna ron SEWING Maonmns Sydney Zonis,

Singer Manufacturing Bridgeport, Conn., assigner to The Company, Elizabeth,

N. J., a corporation of New Jersey Application January 8, 1942, Serial No. 425,961

(Cl. Ilz-228) 19 Claims.

This invention relates to circularly moving loop-taker and thread-carrier devices for lockstitch sewing machines and more particularly to loop-takers such as the rotary hooks disclosed in U. S. patents, Nos. 1,995,278 and 2,085,699, dated Mar. 19, 1935, and June 29, 1937.

A loop-taker of the type in question is provided with a circular raceway in which is journaled a peripheral bearing rib of a substantially cylindrical thread-carrier which houses the lower thread-mass. It is the function of the looptaker to seize a loop of thread from the sewing machine needle, draw out or expand such loop and lcast it about the stationary thread-carrier, after which the needle-thread take-up device of the machine comes into action to draw the needle-loop up to the work and complete the stitch.

In conventional lock-stitch sewing machines which are fitted with rotary loop-takers of the type disclosed in each of the two patents above mentioned, the needle-loop seizing section of the loop-taker is given two rotations for each complete reciprocation of the needle, or, in other Words, for each complete stitch made by the machine. Inasmuch as many of the conventional lock-stitch machines are operated at high speeds, of the order of 5,000 or more stitches per minute, it will be appreciated that the loop-seizing element of the loop-taker must rotate at twice the speed of the needle-operating shaft or, 10,000 or more revolutions per minute. Obviously at this high rate of speed excessive heat is generated by friction 'between the contacting surfaces of the circular raceway and the thread-carrier bearing-rib, with the result that very rapid wear or the interiitting parts takes place notwithstanding the presence of lubricant, which, of necessity, must be sparingly used so as not to stain or soil the thread or material being sewed.

It is lthe primary object of my invention to provide an improved interconnecting means between the movable or loop-seizing element and the stationary or thread-carrier element of a circularly moving loopetaker, whereby the friction generated by the relatively rotating parts is reduced to a minimum.

It is a further object of the present invention to provide an improved means for interconnecting the relatively movable elements of a rotary loop-taker, whereby the extent of wear betweeny the intertting parts is greatly minimized.

With the above and other objects in view, as will hereinafter be obvious, the invention consists in the devices, combination and arrangement of parts hereinafter described in connection with the accompanying drawing which illustrates a preferred embodiment of the invention and in which:

Fig. 1 is a front face elevation of a sewing machine rotary hook and thread-carrier embodying the invention.

Fig. 2 represents a verticalv axial section'taken substantially along the line 2-2, Fig. 1. f

Fig. 3 is a top plan View of the rotary hook and thread-carrier.

Fig. 4 is a rear end hook and thread-carrier.

Fig. 5 represents a vertical section taken sub# stantially along the line 'zi-'5, Fig. 3.

Fig. 6 represents a sectional view vtaken substantially along the line B--6, Fig. 4.' Referring more in detail to the drawing, the rotary hook illustrated comprises a cup-shaped hook-body I having a cylindrical wall I' formed with a loop-seizing beak 2, a hub 3 apertured at 3 to receive the usual hook-shaft, a loop-controlling tail land a circular rconcave outer racevvay 5 in rolling contact with a plurality of uniformly spaced antifriction elements, as for example hardened steel balls 6. Opposing the concave raceway 5 in maintaining the balls 6 in vsnug rollingv contact with said raceway is a circular' concave inner raceway 'I formed in the' peripheral surface of an inner member o'r ring B disposed to rotate freely relative to the hook-body I. Arranged within the'hook-bo'dy is a cup-shaped thread-carrier element preferably consisting of an inner or body-member 9 vand an outer -or cap-member i0 (Fig. 2); the two members being arranged in telescopic relation, with the cap'- member l0 disposed within the lbody-member 9. The body-member 9 of the thread-carrier is preferably made of a base-portion I I and a cylindrical skirt-portion I2 (Fig. 6) disposed substantially parallel to the cylindrical wall l' of the vhook-body I; the two .portions II and I2 being joined together in Yabutting relation, preferably by means 'of screws I3, in a plane containing the geometric center of each of the balls t. Formed inthe contiguous faces of each of the two portions II and I2 of the body-'member 9 are a plurality of cavities which, when the two portions II and I2 are complementa-l relationship, ball-socketsV I4 (Figs. 2 vand 3), in which the balls 6 are rotatably disposed as in the ballcage or separator of a conventional ball-bearing. As clearly seen in Fig. 5, the balls 6 are uniiormly spaced about the periphery of the threadcarrier, with the exception that at the upper provide completed elevation of the rotary arranged in proper ly entered by the usual rotation-restraining bar Y common to rotary lock-stitch sewing machines.

The base-portion II of the body-member 9 is formed with an axial bobbin-supporting post I8 on which is slidably mounted the vtubular arbor I9 of the cap-member ID, which tubularlarbor freely receives the regular bobbin member 20,

see Fig. 2. The cap-member III is secured in po-` sition upon the bobbin-supporting post I8 byfa l latching device, the which are fully disclosed in the previously mentioned U. S. Patent No. 1,995,278. As shown in Fig. 2, the inner end or skirt of the cap-member I0 is reduced in diameter, as at 2|, to provide clearance for the ring 8. When the component parts of the rotary hook are in proper assembled condition, the ring 8 is entirely free of the skirt oi the cap-member III and can (freely rotate or oat at any speed determined by the speed of rotation of the balls 6 in their stationary cage sockets I4.

Referring to Fig, 5 it will be observed that the interengaging parts of 'the rotary hook have an appearance approximating that of a conventional ball-bearing; the hook-body'I providing the outer ball-race 5, the ring 8 providing the inner ball-race 'I, and the body-member 9 with its ball-sockets I4 providing the usual ball-cage or spacer. In the conventional ball-bearing, considering the outer race as being held stationary in a bearing lug, the inner race rotates relatively to the outer race and the balls interposed between the two racesl have substantially pure rolling contact with the respective races. The conventional ball-retainer, of course, is free to rotate in the same direction as'the movable ballrace and Adoes so vat a reduced speed. In the present case, substantially the same effect is accomplished as in the conventional ball-bearing, but in a different manner.V In Figs. 2, 3 and 5, it will be seen thatV the balls 6 are retainedin sockets I4 formed in the body-member 9 of the thread-carrier and it will be understood that the thread-carrier is held stationary during the operation of the hook. The driven member of the hook-assembly is the hook-body I in which is formed the outer race 5 and the member which is free to rotate is the ring 8 in which the inner race 'I is formed. The direction of rotation of the ring 8 isoppositeto that of the hook-body I.

From the above description it will be understood that the improved bearing means between the circularly moving hook-body and the stationary thread-case of the rotary loop-takerop- Yerates on the same principle as a conventional hall-bearing. The presence of. the ring 8 relieves the ball-sockets I4 of a major portion of the force tending to cause relative lateral displace-v ment between the hook-body l and the threadcarrier and consequently minimizes the friction. resulting from the surface contact of the balls 8 in their respective sockets I4.l With a major portion of this force absorbed by the ring 8 on which the balls 6 roll, as in a conventional ball-- bearing. the extent of wear between the balls 6 constructive features of4 and their respective sockets I4 is exceedingly small. Since the body-member 9 serves primarily as a retainer to maintain the balls 6 separated and in proper position during their passage through the gap between the loop-seizing beak 2 and the loop-controlling tail 4, the pressure between the balls and their respective sockets is very small. This being true it will be appreciated that the amount of friction and the resultant heat generated between the balls 6 and their sockets I4 will be very small. Furthermore, since the balls 6 are mounted in sockets which are stationary, the ease with which the balls rotate in their respective sockets is not affected by Y, centrifugal force, which would be the case if the balls were journaled in sockets provided in the rotating parts of the hook.

From the foregoing it will be realized that I have. invented a circularly moving loop-taker for lock-stitch sewing machines, which looptaker may be operatedsat high rates of speed for long periods of operation without overheating or wearing excessively and without requiring substantial amounts of lubricant to attain these desirable results. It will, of course, be understood that I have merely illustrated and described va preferred embodiment of the invention and that modifications may be made in the design of the parts without departing from the invention as determined by the appended claims. It will be obvious that small cylinders may be used as antifrictional elements in place of the balls as illustrated, inY which case the sockets I4 vwill be appropriately shaped to properly retain them in place.

Having thus set forth the nature of the invention what I claim herein is:

l. A rotary loop-taker for sewing machines comprising, a rotary loop-seizing element, a.

thread-carrier element journaled in and adapted to be restrained against rotation with said rotary loop-seizing element, said thread-carrier element having a plurality of sockets provided inA the periphery thereof, and antifrictional members disposed in said sockets and having bearing contact with said rotary loop-seizing element.

2. A rotary loop-taker for sewing machines comprising, a cup-shaped rotary loop-seizing ele-l ment having a cylindrical wall provided with an internal circumferential raceway, a cup-shaped thread-carrier element disposed within said rotary loop-seizing element and adapted to be restrained against rotation with said loop-seizing,

element, said cup-shaped thread-carrier element having a cylindrical skirt-portion disposed substantially parallel to said cylindrical wall of said rotary loop-seizing element, Aand antifriction means provided in said cylindrical"skirt-portion and having bearing contact with said raceway of said'loop-se'izing element. Y'

3. A rotary loop-takerfor sewing machines comprising, a cup-shaped rotary loop-seizing'ele-v ment having a cylindrical wall provided with an internal circumferential raceway,V a cup-shaped thread-carrier element disposed'within said rotary loop-seizing element and adapted to be restrained against rotation with said loop-seizing element, said cup-shaped thread-carrier element having a cylindrical skirt-portion positioned adjacent said cylindrical wall of said rotary loopseizing element and provided with a plurality of sockets, and antifrictional members disposed in said sockets and having bearing contact withsaid raceway of said loop-seizing element.

4,'A rotary loop-taker for sewing machines of cavities formed in the end 'fa-ce `of said skirtcomprising, a rotary loop-seizing element provided with an internal circumferential raceway, a thread-carrier element disposed within said rotary loop-seizing element and adapted to be restrained against rotation with said loop-seizing element, said thread-carrier 'element including separable base and skirt portions, means for securing said base and skirt portions together, and a plurality of antir'rictional members carried by said thread-carrier element at the junction of said base and skirt portions and having rolling bearing contact with said raceway in said rotary loop-seizing element.

5. A rotary loop-taker for sewing machines comprising, a rotary loop-seizing element provided with an internal circumferential raceway, a thread-carrier element disposed within said rotary loop-seizing element and adapted to be restrained against rotation with said loop-seizing' element, said thread-carrier element including two parts joined together in abutting relation, each of said parts having for-med therein a plurality of cavities which when the two partsu of said thread-carrier element are united together register to provide completed sockets, means for securing the two parts of said thread-carrier element together, and antifrictional elements disposed in said sockets and having bearing contact with said raceway in said rotary loop-seizing element.

6. A rotary loop-taker for sewing machines comprising, a cup-shaped rotary loop-seizing element having a cylindrical wall provided with a loop-seizing beak and with an internal circumferential raceway, a cup-shaped thread-carrier element disposed within said rotary loop-seizing element and adapted to be restrained against rotation with said loop-seizing element, said cupshaped thread-carrier element including a basesection and a skirt-section having abutted faces, each of said baseand skirt-sections provided in their abutting faces with a plurality of cavities which when the two sections of lsaid thread-carrier element are united together register to form completed sockets, means for securing the two sections of said thread-carrier element together, and antifrictional elements disposed in said sockets and having bearing Contact with said raceway in said rotary loop-seizing element.

'7. A rotary loop-taker for sewing machines comprising, a rotary loop-seizing element havingl a loop-seizing beak and an internal circumferential raceway, a thread-carrier element disposed within said rotary loop-seizing element and adapted to be restrained against rotation with said loop-seizing element, a plurality of antifrictional elements carried by said thread-carrier element and having bearing contact with said raceway in said rotary loop-seizing element, a pair of said antifrictional elements being spaced apart a sucient distance to provide a gap therebetween, a needle-loop-detaining shoulder defining one end of said gap, and a needle-loop confining shoulder defining the other end of said gap.

8. A rotary loop-taker for sewing machines comprising, a rotary loop-seizing element having a loop-seizing beak and an internal circumfer-A ential raceway, a thread-carrier element disposed within said loop-seizing element and adapted to be restrained against rotation therewith, said thread-carrierelement including a base-portion having a plurality of cavities provided in the periphery thereof and a cylindrical skirt-portion abutting said base-portion and having a plurality disposed in said sockets and having portion contiguous with said base-portion, a bobbin-supporting post arranged axially'of and attached to said base-portion, means for securing said base-portion and skirt-portion together with their respective cavities in register to form a plurality of completed sockets spaced about the periphery of said thread-carrier element, a pair of said sockets being spaced apart a suiiicientV distance to provide a substantial gap, a needlethread-loop detaining shoulder dening one end of said gap, a needle-thread-loop conning shoulder defining the other end of said gap, andv antifrlctional elements disposed in said completed sockets and having bearing Contact with said raceway in said icon-seizing member.

9. A rotary loop-taker for sewing machines comprising, a rotary element provided with a loop-seizing beak and a raceway, a thread-carrier element cooperating with said rotary element and adapted to remain stationary during rotation of said rotary element, antifrictional means sustained by said thread-carrier element and having bearing contact with said raceway of said rotary element, and means for maintaining said antifrictional means in snug bearing contact with said raceway of said rotary element.

10. A rotary loop-taker for sewing machines comprising, an outer rotary element provided with a loop-seizing beak and a raceway, a threadcarrier element disposed within said outer rotary element and adapted to be restrained against rotation with said outer rotary element, a plurality of antifrictional means sustained by said threadcarrier element and having bearing contact with said raceway of said outer rotary element, and means cooperating with all of said antifrictional means for maintaining said antifrictional means in snug bearing contact with said raceway of said outer rotary element.

ll. A rotary loop-taker for sewing machines comprising, an outer rotary element provided with a loop-seizing beak and a racewa a threadcarrier element disposed within said outer rotary element and adapted to be restrained against rotation with said outer rotary element, antifrictional means sustained by said thread-carrier element and having bearing contact with said raceway of said outer rotary element, and means positioned within said thread-carrier element for maintaining said antifrictional means in snug bearing contact with said raceway of said outer rotary element.

12. A rotary loop-taker for sewing machines comprising, an outer rotary element provided with a loop-seizing beak and yan outer raceway, an inner rotary element disposed within sai-d outer rotary element and provided with an inner raceway, a thread-carrier element adapted to be restrained against rotation with said outer` rotary element, and antifrictional bearing means carried by said thread-carrier element and interposed between said outer and inner raceways.

13. A rotary loop-taker for sewing machines comprising, an outer rotary element provided with a loop-seizing beak and an internal circumferential raceway, an inner rotary `element disposed within said outer rotary element and provided with an inner raceway, a thread-carrier element adapted to be restrained against rotation with said outer rotary element, said thread-carrier element having a portion thereof disposed between said inner and outer rotary elements provided with a plurality yof sockets, and antifrictional elements rolling :con-

inner and outer inner raceway, a thread-carrier element adapted to remain stationary during rotation of said outer rotary element, and antifri-ctional bearing elements carried by said thread-carrier element and interposed between said outer and inner raceways.

15. A rotary loop-taker for sewing machines comprising, a cup-shaped rotary loop-seizing element having a cylindrical wall provided with, an internal circumferential raceway, a cup-shaped thread-carrier element disposed within said ro-r tary loop-seizing element and adapted to be restrained against rotation With said loop-seizing element, antifrictional elements carried by said thread-carrierelement and having bearing contactwith said raceway in said rotary loop-seizing element, and a member disposed within said.

thread-carrier element and lprovided With a second raceway for maintaining said antifrictional elements in snug bearing contact with said raceway in said loop-seizing element.

16. A rotary loop-taker for sewing machines comprising, a .cup-shaped rotary loop-seizing element having a cylindrical wall provided with an internal circumferential'raceway, a cupshaped thread-carrier element disposed within said ro tary loop-seizing element and adapted to be restrained against rotation withV said loop-seizing element, said cup-shaped thread-carrier having a plurality of sockets spaced about the periphery thereof, antifrictional elements disposed in said sockets and having bearing contact with said raceway in said rotary loop-seizing element, and a member disposed within said thread-carrier element and provided with a second raceway for maintaining said antifrictional elements in snug bearing contact with said raceway in said loopseizing element.

17. A rotary loop-taker for sewing machines comprising, a cup-shaped rotary loop-seizing ele ment having a cylindrical wall provided with an internal circumferential raceway, a cup-shaped thread-carrier element disposed within said rotary loop-seizing element and adapted to be restrained against,V rotation with said loop-seizing element, antifrictional elements carried by said thread-carrier element and having bearing contact with said raceway in said rotary loop-seizing element, and a ring disposed for free turning movement within said thread-carrier element and provided in its periphery with a second raceway for maintaining said antifrictional elements in snugbearing contact with said raceway in said loop-seizing element. f

, 18. A rotary loop-taker for sewing machines comprising, a rotary loop-seizing element having a loop-seizing beak and an interna] circumferential raceway, a thread-carrier element disposed within said loop-seizing element and adapted to be4 restrained against -rotation therewith, a bobbin-supporting post attached to said thread-carrier element, la plurality of antifrictional elements l carriedby said thread-,carrier element and having bearing 4contact with said raceway in said loopseizing element, a ring disposed within said thread-carrier element and provided with a second raceway for maintaining said antifrictional elements in snug bearing contact with said raceway in Vsaid loop-seizing element, and a cap-member secured to said bobbin-supporting post, said cap-member having a cylindrical skirt formed with a. reduced portion to provide clearance for said ring.

19; A rotary loop-taker for sewing machines comprising, a rotary loop-seizing element, a thread-carrier element journaled in and adapted to be restrained against rotation with said loopseizing element, and antifrictional journaling means supporting said thread-carrier within said rotary loop-seizing element and restrained against rotation with saidrotary loop-seizing element.

SYDNEY ZONIS. 

